Mmap'd open-addressing hash table (~49KB/day) records which memory
keys get retrieved. FNV-1a hash, linear probing, 4096 slots.
- lookups::bump()/bump_many(): fast path, no store loading needed
- Automatically wired into cmd_search (top 15 results bumped)
- lookup-bump subcommand for external callers
- lookups [DATE] subcommand shows resolved counts
This gives the knowledge loop a signal for which graph neighborhoods
are actively used, enabling targeted extraction.
Co-Authored-By: ProofOfConcept <poc@bcachefs.org>
